1. Field of the Invention
This invention relates to a circuit and a method for generating a low-level current using semiconductor charge pumping.
More particularly this invention relates to a means of generating a range of current sources by varying the frequency of a repetitive voltage pulse input signal.
Also, this invention relates to utilizing one or many MOSFET devices in order to produce higher levels of current.
In addition, this invention relates to the ability to generate very stable current sources with high input impedances.
2. Description of Related Art
The prior art related to this invention includes various high input impedance low level current sources. Typically, these current sources are custom designed monolithic circuits. They are not modular or are they scalable from the lowest current level produced by a single device to high current levels produced by hundreds of device.
U.S. Pat. No. 6,285,243 B1 (Mercier et al.) “High Voltage Charge Pump Circuit” describes a circuit which transfers a voltage signal in an output stage without signal level degradation. By-pass techniques are used to avoid semiconductor damage or breakdown.
U.S. Pat. No. 6,326,839 B2 (Proebsting) “Apparatus for Translating a Voltage” discloses a low voltage current source is used for translating voltage levels using a charge pumping mechanism.
U.S. Pat. No. 6,323,721 B1 (Proebsting) “Substrate Voltage Detector” discloses low voltage current source circuit, which generates low voltage signals for powering a variable frequency oscillator.
U.S. Pat. No. 5,561,385 (Choi) “Internal Voltage Generator for Semiconductor Device” discloses an internal voltage generator for a semiconductor device, for generating an internal voltage within the device.
U.S. Pat. No. 6,278,315 (Kim) “High Voltage Generating Circuit and Method for Generating a Signal Maintaining High Voltage and Current Characteristics Therewith” discloses a high voltage generating circuit, which is used to generate a high voltage with a high current. This circuit is used for on-chip programming and erasing of electrically erasable programmable read only memory EEPROM or flash memory.